SpaceX’s Falcon 9 rocket lifted off for the first time in five months to put 10 advanced Iridium Next telecommunication sateliites in orbit – and demonstrate that the company’s innovative launch-and-landing system was back in stride.

Cheers went up from a crowd of hundreds of SpaceX employees at the company’s headquarters as they watched the rocket ascend from California’s Vandenberg Air Force Base at 9:54 a.m. PT. The cheers rose again minutes later when the Falcon 9’s first stage landed on a drone ship in the Pacific for the first time.

That blow-up forced a months-long suspension, during which SpaceX determined that the failure was caused by problems with a helium pressure vessel inside the rocket’s second-stage liquid oxygen tank. To head off those problems, SpaceX changed its fueling procedures and will eventually redesign the vessels.

In addition to marking SpaceX’s return to flight, this mission marked the first deployment of Iridium’s next-generation satellites. The satellites were deployed, one by one, into a pole-to-pole orbit to provide mobile and data communication services.

SpaceX is due to put the 70-satellite constellation into place with seven launches over the course of the next year. Iridium Next is designed to deliver faster data transfer speeds and higher throughputs than Iridium’s existing network, representing one of the largest “tech upgrades” in history.

During the eight minutes following launch, the rocket’s second stage and its payload separated from the first-stage booster. While the second stage powered onward to orbit, the first stage went through a series of maneuvers to slow itself down from supersonic speeds and guide itself to an oceangoing drone ship.

SpaceX has successfully landed a Falcon 9 booster six times, including two touchdowns at its “Landing Zone 1” in Florida and four times on a drone ship in the Atlantic. This was the first Pacific touchdown.

Capping off the day’s coverage, launch commentator John Insprucker announced more than an hour after liftoff that all 10 Iridium Next satellites were deployed into their proper orbit.

“It’s a clean sweep, 10 for 10,” he said.

Over the next couple of days, the first-stage booster will be transported back to shore for inspection and refurbishing. Recovering and reusing rocket hardware is a key part of SpaceX’s campaign to drive down the cost of access to space and clear the way for flights to Mars within the next decade. The first launch of a previously flown booster is expected to take place later this year.

That’s not the only highlight on this year’s agenda for SpaceX: The California-based company is also gearing up for the first launch of its Falcon Heavy super-rocket from Vandenberg, as well as its first uncrewed flight test of a Dragon space taxi that’s eventually meant to ferry astronauts to and from the International Space Station.